Method for producing low-k l film, semiconductor device, and method for manufacturing the same

Abstract

Hydrophobicity of a low dielectric constant film comprising a porous silica film is improved by applying a raw material for forming a porous silica film onto a substrate, and performing vapor-phase transport treatment to expose the substrate to an atmosphere of organic amine vapor to which no water is added. Simultaneously, reduction in a dielectric constant, reduction in leakage current, and improvement in mechanical strength are attained by controlling a pore diameter in a predetermined range.

1. A method for producing a low dielectric constant film comprising a porous silica film, the method comprising:
 forming a porous silica precursor film on a substrate by applying a raw material for forming a porous silica film to the substrate; and 
 performing a vapor-phase transport treatment on the porous silica precursor film by exposing the porous silica precursor film formed on the substrate to an atmosphere of an organic amine vapor to which no water is added. 
 
     
     
       2. The method for producing a low dielectric constant film according to  claim 1 , further comprising performing a calcination heat treatment on the porous silica precursor film after the vapor-phase transport treatment. 
     
     
       3. The method for producing a low dielectric constant film according to  claim 1 , wherein the organic amine contains at least a primary diamine. 
     
     
       4. The method for producing a low dielectric constant film according to  claim 3 , wherein the primary diamine is ethylenediamine. 
     
     
       5. The method for producing a low dielectric constant film according to  claim 1 , wherein the organic amine contains at least a tertiary amine. 
     
     
       6. The method for producing a low dielectric constant film according to  claim 5 , wherein the tertiary amine is triethylamine. 
     
     
       7. The method for producing a low dielectric constant film according to  claim 1 , wherein the porous silica film is a film having a pore diameter of 4 to 8 nm shown as an average of a diameter. 
     
     
       8. The method for producing a low dielectric constant film according to  claim 7 , wherein ethylenediamine and triethylamine are used in the organic amine at a volume ratio of 100:0 to 0:100 in a solution state; and the pore diameter is controlled by adjusting a mixing ratio in volume of ethylenediamine and triethylamine. 
     
     
       9. The method for producing a low dielectric constant film according to  claim 1 , wherein the vapor-phase transport treatment is a treatment to hydrophobize the porous silica film, and thereby to prevent moisture absorption by the porous silica film. 
     
     
       10. The method for producing a low dielectric constant film according to  claim 1 , wherein the vapor of the organic amine in the vapor treatment is generated by heating the organic amine to a temperature range of not less than a boiling point of the organic amine and not more than 250° C. 
     
     
       11. The method for producing a low dielectric constant film according to  claim 1 , wherein a temperature of the substrate in the vapor-phase transport treatment is set at 100° C. to 450° C. 
     
     
       12. The method for producing a low dielectric constant film according to  claim 1 , wherein the vapor-phase transport treatment is performed for one to six hours. 
     
     
       13. The method for producing a low dielectric constant film according to  claim 2 , further comprising, after the vapor-phase transport treatment and before the calcination heat treatment,
 rinsing to remove the organic amine adhering to a surface of the substrate; and 
 drying subsequent to the rinsing. 
 
     
     
       14. The method for producing a low dielectric constant film according to  claim 2 , wherein the raw material for forming the porous silica film is produced by synthesis by stirring a silica precursor, a catalyst, water, a solvent, and a pore generator; and the calcination heat treatment is to convert the porous silica precursor film into a porous silica film by decomposing and volatilizing the pore generator not decomposed during the vapor treatment. 
     
     
       15. The method for producing a low dielectric constant film according to  claim 2 , wherein in the calcination heat treatment, a temperature of the substrate is raised from room temperature to 400° C. at a rate of 1 to 20° C./min., and the substrate is heated for one to six hours. 
     
     
       16. A method for manufacturing a semiconductor device having a multilevel interconnect structure, comprising a metal interconnect and an interlayer insulating film, layered each other, on a semiconductor substrate and wherein
 the interlayer insulating film includes a low dielectric constant film, and 
 the low dielectric constant film is produced by the method according to  claim 1 . 
 
     
     
       17. The method for manufacturing the semiconductor device according to  claim 16 , wherein the metal interconnect is formed by burying a groove formed in the interlayer insulating film. 
     
     
       18. The method for manufacturing the semiconductor device according to  claim 16 , wherein the metal interconnect is formed by burying a groove formed in the interlayer insulating film and a contact hole formed on a part of a bottom surface of the groove. 
     
     
       19. The method for manufacturing the semiconductor device according to  claim 16 , wherein the metal interconnect is a cupper interconnect.